The purging or scrubbing of the fuel intake passageways of internal combustion engines by means of introducing fuel mixed with solvent into the fuel intake is not new. It has been appreciated for years that this technique avoids the expensive proposition of dismantling the engine to clean carburetor jets or injectors. Due to the nature of the internal combustion engine, it is inevitable that after a period of time the engine will build up deposits that impede its performance.
Prior art devices have been developed, and until recently have been used by the instant inventor in his own business until he developed the improved purging system that is the subject of this disclosure. It is a principle improvement of the invention that it incorporates both gasoline purging and diesel purging in the same machine, with common portions of the gasoline and diesel systems overlapping. However, there are other features that distinguish the invention from the prior art, and make it possible to provide purging service of such a wide variety of commercially produced internal combustion engines.
Systems that function in the same general manner are disclosed in a number of U.S. patents which will be described below.
U.S. Pat. No. 4,520,773 issued on Jun. 4, 1985 discloses an injection cleaning and testing system which introduces a fuel-cleaning solvent mixture into the engine fuel intake. However, this system is for a single fuel only. It has no fuel mixture return line and utilizes a fuel relief line that does not communicate with the fuel tank, but rather is connected to the pump vacuum line. This is considered a handicap for use with high-volume diesel engines. Although the same system could be used with gasoline or diesel mixtures, because diesel engines, especially large diesels, are substantially different in their fuel intake requirements from gasoline engines, aside from the inconvenience of switching fuels, there is also the problem of not providing cleaning capabilities for the wide range of engines that is possible with the two-in-one system of the instant inventor.
U.S. Pat. No. 4,787,348, issued Nov. 29, 1988 is designed exclusively for the use of diesel engines. Although it uses a mixture tank and a storage tank, both tanks hold the same mixture. This system has no regulator at all, relying on a pre-set relief valve to control fuel delivery pressure.
U.S. Pat. No. 4,877,043, issued Oct. 31, 1989 is stated as being useful for gasoline, small diesel, or methane burning internal combustion engines. It is a single system rather than a dual system, and for this reason is believed to be considerably more limited in its application than the disclosure would lead one to believe. The small size of the pump's fuel ports, hoses, regulators and the overall system design would make it unlikely that this machine could be used on large diesels.
U.S. Pat. No. 4,989,561, issued Feb. 5, 1991 is designed for carbureted and EFI engines and injects the fuel-solvent mixture into the air intake only, rather than the fuel supply line. It is not designed to work with diesel engines or high-pressure injected gasoline systems. It does not clean the fuel passageways and fuel sprayers inside a carburetor, or the fuel rail, fuel regulator or injectors of an injected system, which is the main thrust of the other devices described. It will not work with continuous injection systems (C.I.S.)
U.S Pat. No. 5,063,896, issued Nov. 12, 1991 is actually made to clean the transmission or the oil system of an engine rather than its fuel system.
The number of recent patents falling within this general subject matter area indicates the interest in internal combustion engine purging that has developed in recent years. This is likely because of the relatively recent surging of fuel injected gasoline engines into mainstream car manufacturing.
Despite this display of interest however, there is still a need for a universally applicable purging system effective not only for both gasoline and diesel engines, but also having the true capability of meeting the requirements of very large high-fuel-flow/-volume diesels, but small gasoline engines as well.